[Hot Grits]

So after alot of flip flopping back and forth, I have finally decided on my new build. I would like to thank Chris over at Elemental Designs for his help in designing the enclosure and for answering my millions of questions.


I will be building two enclosures, each housing one 13av.2 driver. Each enclosure will be about 4.5 cubes after subtracting for the port, bracing, etc. They will be tuned to about 17 hz with a slot port. They will be powered by an ep2500.


I was going back and forth in my mind between this design or two 14 cuFT sonotubes with the 19Ov.2 drivers. They were just too big to put in my livingroom without looking ridiculous. I wont have as much output with the 13Av.2 drivers, but I should (hopefully) get some nice low extension.

 

[Hot Grits]

Here are the specs on the driver.


Qts: .45

Qes: .48

Qms: 7.48

Fs: 23.29 Hz

Re: 2.81

Vas: 55.79 L

Mms: 257 g

Bl: 14.81 T*m

SPL: 83.50 dB

Sd: 556 cm^2

Xmax: 28.75 (Physical Linear) mm

Voice Coil: 76MM mm


Magnet Width: 7.50"

Cutout Diameter: 12.00"

Mounting Depth: 10.05"

Weight: 59 lb

Total Height: 10.05"

Displacement: .12 ft^3

Outside Diameter: 13.50"


And this is my attempt at modeling it on WinISD. I am new to all this. So I am unsure if I entered all the parameters correctly.

 

[Hot Grits]

WinIsd.

 

[Hot Grits]

I am sure I am going to have a ton of questions. Thats pretty much why I started this thread. Hopefully some of you experts will be able to guide me through this project.


First off, how does everything look so far? Any suggestions / modifications?


Also I have one question regarding WinISD. What value do I enter for series resistance under the signal tab. I have been leaving it at 0 for my graphs. When I enter 2 ohms, the driver exceeds Xmax in the 22 to 35 hz region. Whats the proper value for this?

 

[Uklit]

The 13Av.2 is avaialable in Dual 2 or Dual 4 ohm coils, which one did you get?

 

[Hot Grits]

I cant order until wednesday. I am returning an A5-350 and that should be there on wednesday according to the shipping company. I am guessing I will be getting Dual 2. I planned on asking them over at eD on what I should be buying. This is my first DIY project, and I am pretty much learning as I go.

 

[Looneybomber]

Dual 4 = a single 2ohm load.

Since you're getting two of them and powering them with one EP2500, having each channel at 2ohms will net a little bit more power. I haven't looked at your graphs, but do you need that extra power, or is it already enough at 4ohms to push it past xmax?


*edit* looking at your excursion graph, you reach xmax with 1200w. The EP2500 puts out ~825w/ch at 2ohms. I would get the dual 4's.

 

[Hot Grits]

This is one thing I dont fully comprehend yet. 2 ohm, 4 ohm etc. How would I figure out the best way to do this?

 

[Hot Grits]

825 w/channel. Thats what it was actually tested to do?


On a side note. Is 50 inches to long for a slot port. I keep hearing not to exceed 36" for a round port. Also my first point resonance is at 131 hz. Do you see that being a problem?

 

[gpmbc]

I have the 13AV.2s in the enclosure described. Ben over at ED was driving 2 of them with an LT1300 so each driving was seeing 650 watts. If using the EP2500 dual 2s would be ideal to give a 4 ohm load and allow for stereo operation and more placement flexibility. Ben said in that configuration they were excursion limited before power became an issue and the EP2500 will have more on tap than the plate amp.

 

[Looneybomber]



Quote:
Originally Posted by gpmbc /forum/post/14179081


I have the 13AV.2s in the enclosure described. Ben over at ED was driving 2 of them with an LT1300 so each driving was seeing 650 watts. If using the EP2500 dual 2s would be ideal to give a 4 ohm load and allow for stereo operation and more placement flexibility. Ben said in that configuration they were excursion limited before power became an issue and the EP2500 will have more on tap than the plate amp.

I'm not saying you or Ben are wrong, but looking at the graph posted, xmax is reached above tuning with 1200w, so 1000w will be safe, 825w will be safe. 600w will still be safe, but why not extract all the power out of the amp you can since you're paying the same price for it?


But you say Ben was reaching the excursion limits of the driver with just 500w? (I refuse to believe the LT1300 puts out more than 1000w without drastic amounts of distortion) Was this above or below tuning?

 

[armystud0911]

Depends, Ben may not be factoring the use of a high pass filter, below the tuning, it is entirely possible that the driver would bottom with less than 600 watts.

 

[nik1818]

13Av.2's have so much rear clearance that it takes a lot more power than they can handle thermally to make them bottom out. as far as power handling goes, you won't have to worry with two of them on an EP2500. it's not strong enough to hurt them. i saw one running free air at 10 Hz on an EP2500 bridged at 4 ohms, with all kinds of distortion and clipping and things being thrown at it. The beast went over ten minutes before it locked up. The coil came apart from all the heat. The amp was starting to smell really bad, too.


I've also seen the two running on the LT1300, and to be honest, i didnt think it was enough power because they just weren't moving much. We really didn't beat on them too hard, but they were certainly not being stressed.

 

[Hot Grits]

so I will be getting the D4s I suppose each powered by 1200 watts into 2 ohms. Like someone said above, if it only puts out 825 watts, I dont think I should have a problem with exceeding above tuning.


While I am ordering this, should I pick up an eQ2 to use the subsonic filter? Are there any other options for the SSF. I really wanted to use a BFD for EQ. But if I get the eQ2, I will probably just use that.


Anyway, I'll be headed off to homedepot tomorrow to pick up the MDF. What do you think about bracing for the box? I was planning on two horizontal window style braces evenly spaced inside.

 

[Hot Grits]

One question before I go buy the materials. For the baffle. I am going to double up on it. Should one layer be plywood so screws to attatch the driver "grab" better. Or will I be fine with the MDF.


Should I have a 12" cutout on one and a 13.5" on the other, so I can recess the driver? If yes should I cut 2 panels with a 12" cutout and one with a 13.5" hole. Or is that overkill.

Should I also double up the top by the port opening, or is 3/4 fine all around, except for the driver baffle?


Sorry for the stupid questions

 

[gpmbc]



Quote:
Originally Posted by Looneybomber /forum/post/14179454


I'm not saying you or Ben are wrong, but looking at the graph posted, xmax is reached above tuning with 1200w, so 1000w will be safe, 825w will be safe. 600w will still be safe, but why not extract all the power out of the amp you can since you're paying the same price for it?


But you say Ben was reaching the excursion limits of the driver with just 500w? (I refuse to believe the LT1300 puts out more than 1000w without drastic amounts of distortion) Was this above or below tuning?

He didn't get into specifics just assured me that my Crown K2 was more than adequate at 4ohms per side.

 

[Looneybomber]



Quote:
Originally Posted by Hot Grits /forum/post/14180828


While I am ordering this, should I pick up an eQ2 to use the subsonic filter? Are there any other options for the SSF. I really wanted to use a BFD for EQ. But if I get the eQ2, I will probably just use that.

Well, until someone learns how to modify the HP filter on the EP2500 to make it a SSF (same thing, just different freq), you'll still need something and the eQ can work.

 

[Hot Grits]

Alright guys, One last question before I start building.


Do you think the fold in my port is a problem?


I can also put the entrance to the port on the face of the cabinet up top and have it run along the top and down the back wall.


The only thing with doing that is that it would terminate fairly close to the driver.

 

[AlexE]

A slot port with 90 bends instead of a full 360 would also be better i think. Yes, generally any bends are considered a disadvantage especially sharp ones but slot ports seem to be more resilient to it, this I'm not sure about though. Just hear-say from car forums.


Mixing ply with MDF is recomended by some builders due to different resonances, so it can't hurt.


Why not a round port? Much less work, and seems doable with a fairly tall enclosure like that. Pipe+flares+glue=cheap and easy.


Recesing the driver is good stuff aesthetically. If you're going downfiring it doesn't matter that much, up to you. If you're making those holes with a router, recessing is super easy - might as well if you feel like going all out.

 

[Hot Grits]

I would much rather go with a round port. When I model a 4" port, The port velocity is a problem. A 6" port would have to be 54" long for a 17hz tune. I actually increased the width of the box by an inch. So it is down to 48" high.


If I use 90 degree bends with the slot port. It would terminate only a few inches from the driver. Would that be a problem?